28518173938081 has 27 divisors (see below), whose sum is σ = 29084379630579. Its totient is φ = 27962954421552.

The previous prime is 28518173938063. The next prime is 28518173938109. The reversal of 28518173938081 is 18083937181582.

The square root of 28518173938081 is 5340241.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 15501346980625 + 13016826957456 = 3937175^2 + 3607884^2 .

It is not a de Polignac number, because 28518173938081 - 2²⁹ = 28517637067169 is a prime.

It is a super-2 number, since 2×28518173938081² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28518173998081) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 76456230211 + ... + 76456230583.

It is an arithmetic number, because the mean of its divisors is an integer number (1077199245577).

Almost surely, 2^{28518173938081} is an apocalyptic number.

28518173938081 is the 5340241-st square number.

28518173938081 is the 2670121-st centered octagonal number.

It is an amenable number.

28518173938081 is a deficient number, since it is larger than the sum of its proper divisors (566205692498).

28518173938081 is an frugal number, since it uses more digits than its factorization.

28518173938081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1230 (or 615 counting only the distinct ones).

The product of its (nonzero) digits is 23224320, while the sum is 64.

The spelling of 28518173938081 in words is "twenty-eight trillion, five hundred eighteen billion, one hundred seventy-three million, nine hundred thirty-eight thousand, eighty-one".